Human papilloma virus appears to be associated with the development of cervical carcinoma, a malignant condition which appears to be preceded by several stages of cervical intraepithelial neoplasia (CIN). The association of HPV infection with CIN has long been recognized (Meiseles, A., et al, Gynecol Oncol (1981) 12: 3111-3123; Crum, C. P., et al, ibid (1983) 15: 88-94; Syrjanen, K. J., Obstet Gynecol Surv (1984) 39: 252-265). In fact, IgG reactive with a group-specific papilloma virus antigen was detected in 93% of women with cervical carcinoma and 60% of those with CIN, but not in any control subjects (Baird, P. J., Lancet (1983) ii: 17-18), and the presence of HPV DNA in these lesions has been recognized by several groups.
There are approximately forty different types of HPV, which are classified by DNA sequence homology using hybridization techniques. Samples having more than 50% homology, as judged by hybridization, are placed into the same type designation. The various types appear to be rather tissue specific. HPV-6, HPV-11, HPV-16, HPV-18, and HPV-31 appear to be associated with the genital tract; others appear to be associated with warts or epidermal dysplasias in other tissues. However, HPV-6 and HPV-11 are associated with condyloma type lesions, while HPV-16, HPV-18 and HPV-31 are associated with cervical intraepithelial neoplasia, including invasive carcinoma.
The relationship of HPV infection to the development of CIN and cervical carcinoma is unclear, however it has been postulated that HPV acts as an initiator in cervical carcinogenesis and that malignant transformation depends on interaction with other factors (Zur Hausen, H., et al, Lancet (1982) ii: 1370). The incidence of HPV infection appears to be increasing as shown by a 700% increase in patient visits related to genital HPV infections in both males and females between 1966 and 1981 (Center for Disease Control: Nonreported Sexually Transmitted Diseases (1979) MMWR 28: 61) and the presence of HPV in more than 3% of pap smears of women under 30 (Ferenczy, A., et al, Am J Surg Pathol (1981) 5: 661-670).
The nature of HPV-16 in particular, and papilloma viruses in general has been well studied recently. HPV-16 is a member of the Papova virus group and contains a 7904 bp double-stranded DNA genome (Siedorf, K., et al, Virology (1985) 145: 181-185). The capsid is 50 nm and contains 72 capsomers (Klug, A., J. Mol Biol (1965) 11: 403-423). There are a number of subtypes of HPV-16 which are isolates showing greater than 50% homology (Coggin, Cancer Research (1979) 39: 545-546), but differences in restriction in endonuclease patterns.
The DNAs of several papilloma viruses have been sequenced, including several HPV types, bovine papilloma virus (BPV) and cottontail rabbit papilloma virus (CRPV). All of these display similar patterns of nucleotide sequence with respect to open reading frames. The open reading frames can be functionally divided into early region (E) and late regions (L); the E region is postulated to encode proteins needed for replication and transformation; and L region to encode the viral capsid proteins (Danos, O., et al, J. Invest Derm (1984) 83: 7s-11s).
The detection of HPV in cervical samples has been different because there is no tissue culture system capable of supporting virus harvested from the tissue to be tested through its replication cycle (Tichman, et al, J Invest Derm (1984) 83: 25-65). There is, however, a recently reported in vitro transformation assay (Yasumoto, S. J. Virol (1986) 57: 572-577). Tsurokawa, U. et al Proct Nat'l Acad Sci (USA) (1986) 83: 2200-2203. It is believed that because of analogy with the better studied BPV and CRPV systems, the proteins encoded by several early open reading frames, for example, E6, E5, E7 and E2 (see FIG. 1) are important in HPV genital infections. However, no system for utilization of peptides associated with these regions has been suggested either as an aid to diagnosis or in the synthesis of a vaccine.